The membranes of the surface and internal organelles of normal and virus-transformed (malignant) cells in tissue culture are to be compared. Double-label methods using H3 and C14 L-fucose or D- glucosamine have been used to detect differences in the carbohydrate components of the membrane glycoproteins. The sialyl transferase responsible for the observed differences will be isolated from normal and transformed cells and will be further studied. Attempts will be made to link the chemical alteration to changes in cell behavior and to nuclear events. We now plan to isolate some major proteins and glycoproteins from the various membrane systems of the cells in sufficient quantity for chemical and immunological analysis. Materials derived from normal and transformed cells will be compared.